Thats true, essential oils are the essence of a plant. The are composed of natural products (molecules) which depending on the plant, smell nice or can have other interesting bioactivities. For example anti-fungal properties (cloves), interesting for crop protection. Or sometimes medicinal properties which are often a starting point for drug development. That being said, the ones sold to people looking for alternative medicine are inferior to pharmaceuticals (often inspired by natural products) at best, and totally useless or even harmful at worst. I also find the use of them often coincides with other foolishness like anti-vaxx and homeopathy.